JP2006023847A - Automatic controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic control method which can efficiently compute a control parameter even in a control system in which a large dead time factor of one sampling time or more exists, and can acquire desired control performance. <P>SOLUTION: In the automatic control method for performing motion control of the angle or position of a controlled object in a closed-loop toward a desired value based on a generated control signal, a difference signal is generated according to a difference between the angle or position of the controlled object at present and its desired value, a control parameter for performing motion control of the controlled object is computed, and on the basis of a control function using the computed control parameter, a control signal is generated by performing predetermined arithmetic processing regarding the generated difference signal. From a pole of a closed-loop transfer function in the closed-loop and on the basis of an arithmetic expression including the dead time factor in the closed-loop, the control parameter is computed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automatic control device and method configured by a closed loop for controlling an operation of an angle or a position of a control target toward a target value, and a control parameter generation device for supplying control parameters to the automatic control device, and Regarding the method.

  Conventionally, there has been proposed a PID control device that controls an object to be controlled by combining control of proportional operation, integration operation, and differentiation operation.

The control parameter adjustment in the control system constituting the PID control device is performed by evaluating the response while changing the proportional gain K _p , the differential gain K _d , the integral gain K _i, etc. by trial and error. Since the relationship between the control parameter and the response is not clear, there is a problem that skill is required for the adjustment, and a great deal of time is required for this.

  Furthermore, the control parameter adjustment by trial and error cannot identify the performance limit in the control system. In other words, if performance exceeding a certain level is not obtained after executing the adjustment, it has been determined that this is a limit without searching for a more optimal control parameter.

  For this reason, in order to solve such a problem, a control device to which PID control is applied has been proposed in the past (for example, see Patent Document 1). In this Patent Document 1, a method of calculating a control parameter by variable conversion from the pole and zero of a transfer function of a control system is also disclosed in order to easily adjust the control parameter.

  FIG. 18 shows the configuration of the control device proposed in Patent Document 1. The control device 8 includes a control calculation unit 98 having a subtractor 31, a feedforward (FF) control calculation unit 32, a feedback (FB) control calculation unit 33, and an adder 34, a D / A converter 36, a variable The controller 300 includes a conversion unit 37, a variable setting unit 38, an optimum pole arrangement calculation unit 39, and a sampler 104. The motor 41 is controlled via the motor driver 42, and the control result is obtained by the encoder 200. It is detected as a position signal and negatively fed back to the subtractor 31.

This control device 8 is a device that controls a controlled object such as an arm of an industrial robot using a motor as an actuator, and is based on sampling control based on a sampling control theory, and feedforward control with respect to a target command, and a target command And a control that combines feedback control with respect to the deviation from the actual detection signal. These feedback control and the feedforward control, the control parameter _K p as described _above, K d, are used _{K i.} The feedback control formula and the feedforward control formula are shown in formula (72) and formula (73), respectively.

The control unit 8, the control parameters K _p, K d, _{was added} to the _{K i,} 0-order feedforward gain alpha, in order to easily perform the adjustment of the primary (speed) feed control parameters such as forward gain beta, variable Control parameters are calculated by variable conversion from the poles and zeros of the transfer function of the control system using the conversion unit 37, variable setting unit 38, and optimum pole arrangement calculation unit 39. That is, the control device 8 specifically calculates control parameters according to the command values a, b, c, f, and g of the poles and zeros in the z coordinate system shown in FIG. The calculated control parameter is used for actual control in the FF control calculation unit 32 and the FB control calculation unit 33.

That is, the control device 8 appropriately controls the control parameters K _p , K _d , K _i , α, β to better control the control target according to the proportional operation, the differential operation, and the integration operation. It is possible to obtain the optimal control parameter without trial and error by the optimal pole placement calculation for determining the control parameter.

  Conventionally, an adaptive control type control apparatus as shown in Patent Document 2, for example, has also been proposed. In this conventional adaptive control type control device, the optimum pole placement calculation unit 39 performs computation based on a pole placement formula assuming a quadrupole, that is, a quintic equation of z. However, since this is less than the conventional case of performing double iterative calculation, it is possible to calculate the optimum pole arrangement more easily and quickly. Further, it is possible to make adjustment after grasping the limit of performance, and it is possible to perform efficient control parameter adjustment.

JP-A-8-171402 JP 2000-322104 A

  However, since the calculation of the control parameter described above assumes only a calculation time delay of one sampling time, if there is a dead time element larger than one sampling time in the actual control system, the pole-zero arrangement is used. There is a difference between the specified response and the actual response, and the response cannot always be specified accurately. Further, since the limit of performance is lower than the limit obtained from the control parameter, the adjustment is continued in a state where the limit cannot be grasped well, so that the adjustment efficiency of the control parameter cannot be improved.

  In particular, in a digitized PID control system, it is not uncommon that a dead time element larger than one sampling time exists for some reason, and a demand for improvement in the adjustment efficiency of such control parameters is still great.

  Therefore, the present invention has been devised in view of the above-described problems, and can control a control parameter efficiently even in a control system in which a dead time element larger than one sampling time is present. It is an object of the present invention to provide an automatic control apparatus and method capable of obtaining control performance, and a control parameter generation apparatus and method for calculating control parameters and supplying them to the automatic control apparatus.

  In order to solve the above-mentioned problem, the present inventor is based on a control function using a control parameter calculated from a pole of a closed loop transfer function in a closed loop based on an arithmetic expression including a time delay element in the automatic control device. An automatic control apparatus and method for controlling a control system and a control parameter generation apparatus and method have been invented.

  That is, the automatic control apparatus to which the present invention is applied is an automatic control composed of a closed loop that controls the angle or position of the control target toward the target value based on the generated control signal in order to solve the above-described problem. In the apparatus, the difference signal generating means for generating a difference signal according to the difference of the current angle or position of the control target with respect to the target value, the control parameter for controlling the operation of the control target, and the calculated control parameter Control calculation means for generating a control signal by performing a predetermined calculation process on the difference signal generated by the difference signal generation means based on the control function using the control signal, the control calculation means is a closed loop transfer function in the closed loop From the poles, the control parameter is calculated based on an arithmetic expression including a time delay element in the automatic control device.

  Further, an automatic control method to which the present invention is applied is an automatic control method for controlling the angle or position of a control target toward a target value in a closed loop based on a generated control signal in order to solve the above-described problem. A difference signal generation step for generating a difference signal according to a difference of the current angle or position of the control target with respect to a target value, a control parameter for controlling the operation of the control target, and a control using the calculated control parameter And a control calculation step of generating a control signal by performing a predetermined calculation process on the difference signal generated in the difference signal generation step based on the function, and in the control calculation step, from the pole of the closed loop transfer function in the closed loop The control parameter is calculated based on an arithmetic expression including a dead time element in the closed loop.

  Further, in order to solve the above-described problem, the control parameter generation device to which the present invention is applied is configured by a closed loop that controls the operation of an angle or a position of a control target toward a target value based on the generated control signal. A difference signal generation unit that generates a difference signal according to a difference of the target angle or position with respect to a target value at the present time, and a predetermined calculation process based on a control function for the difference signal generated by the difference signal generation unit Parameter calculation for calculating a control parameter for controlling the operation of a controlled object in a control parameter generation device for supplying a control parameter constituting a control function to a control device having a control means for generating a control signal by Means for calculating the parameter from the pole of the closed loop transfer function in the closed loop to the automatic control device. Kicking calculates the control parameter based on the arithmetic expression including a dead time element.

  In addition, the control parameter generation method to which the present invention is applied includes a closed loop that controls the operation of the angle or position of the control target toward the target value based on the generated control signal in order to solve the above-described problem. A difference signal generation unit that generates a difference signal according to a difference with respect to a target value of an angle or a position of a target at the present time point, and a predetermined calculation process is performed on the difference signal generated by the difference signal generation unit based on a control function Parameter calculation method for calculating a control parameter for controlling the operation of a controlled object in a control parameter generation method for supplying a control parameter constituting the control function to a control device having a control unit for generating a control signal by A control parameter calculation step, from the pole of the closed loop transfer function in the closed loop, the control Based on the arithmetic expression including a dead time element in the location, it calculates the control parameter.

  In the present invention, the control system is controlled based on the control function using the control parameter calculated based on the arithmetic expression including the time delay element in the automatic control device from the pole of the closed loop transfer function in the closed loop. As a result, in a control system with a large dead time element, the number of poles that cannot be controlled increases, but the poles can be specified exactly as many as the number of control parameters, and the control characteristics can be specified directly at the pole positions of the closed-loop transfer function. In addition, the control parameter can be obtained by the pole placement method. At this time, the pole placement can be realized accurately by calculating the control parameter according to the pole placement formula (calculation formula) derived from the closed loop transfer function including the dead time approximated to an integral multiple of the sampling time. The desired control performance can be obtained.

Hereinafter, as the best mode for carrying out the present invention, an automatic control device configured by a closed loop that controls an angle or a position of a control target toward a target value based on a generated control signal is applied to a motor. The system will be described as an example. By the way, the present invention
Needless to say, the present invention can be applied to rotating systems other than motors and linear motion systems without departing from the gist.

  As shown in FIG. 1, the automatic control device 1 generates a control calculation unit 10 that outputs a control signal by executing predetermined calculation processing, and generates control parameters necessary for a control function in the control calculation unit 10. A control parameter generation unit 18; a control parameter calculation unit 20 that actually calculates control parameters generated by the control parameter generation unit 18; a zero-zero arrangement input unit 30 that sets numerical values for the control parameter calculation unit 20; The stability determination unit 40 connected to the control parameter calculation unit 20, the display unit 111 for displaying the result of the stability determination in the connected stability determination unit 40, and the digital control signal output from the control calculation unit 10 are analog A D / A conversion circuit 50 for converting the control signal into a control signal, and a drive mode according to the digital control signal output from the D / A conversion circuit 50. A motor driver 60 for adjusting the power supplied to the motor M, and includes an encoder 70 for detecting the rotation angle of the drive motor M, and a sampler circuit 80 for sampling the rotation angle detected by the encoder 70 at a constant period.

  The control calculation unit 10 outputs a control signal by a PID operation that combines a proportional operation, a differentiation operation, and an integration operation. The control calculation unit 10 includes a feedforward (FF) control calculation unit 11, a feedback (FB) control calculation unit 12, , A first adder circuit 13 and a second adder circuit 14 are provided.

Each of the FF control calculation unit 11 and the FB control calculation unit 12 includes a control function as shown in FIG. 1, and a proportional gain K _p , a differential gain K _d , and an integral gain K _i as control parameters of the respective control functions. , Feed forward gain α and velocity feed forward gain β. Incidentally, T indicates a sample period in the sampler circuit 80.

  The FF control calculation unit 11 generates feedforward control data for feedforward control of the rotation operation of the drive motor M based on the target angle r inputted from the outside and the control function shown in FIG. Is output to the second adder circuit 14.

  The first addition circuit 13 adds the rotation angle data of the driving motor M input from the sampler circuit 80 and the target angle r, and outputs the addition result to the FB control circuit 12 as an angle error e.

  The FB control calculation unit 12 generates feedback control data for feedback control of the rotational operation of the drive motor M based on the angle error e added by the first addition circuit 13 and the control function shown in FIG. The generated feedback control data is output to the second adder circuit 14.

  The second addition circuit 14 adds the feedforward control data generated by the FF control calculation unit 11 and the feedback control data generated by the FB control calculation unit 12, and uses the addition result as a control signal as a D / A conversion circuit. 50 is output.

  The D / A conversion circuit 50 converts the digital control signal output from the control arithmetic unit 10 into an analog control signal, and outputs the analog control signal to the motor driver 60.

  The motor driver 60 controls the rotation operation of the drive motor M by adjusting the electric power supplied to the drive motor M based on the analog control signal.

  The encoder 70 detects the rotation angle y of the drive motor M. The sampler circuit 80 samples the rotation angle y of the drive motor M detected by the encoder 70 at a constant period T and outputs it as rotation angle data.

The control parameter calculation unit 20 calculates the control parameters K _p , K _d , K _i , α, and β used for each control function of the control calculation unit 10 based on the numerical values specified by the pole-zero arrangement input unit 30. The calculation result is output to the control calculation unit 10.

  That is, the control parameter generation unit 18 inputs a desired pole-zero arrangement in the closed-loop transfer function in the pole-zero arrangement input unit 30, and the control parameter calculation unit 20 calculates a control parameter for realizing the pole-zero arrangement. At this time, stability determination is performed by the stability determination unit 40 using only the coefficients of the polynomial obtained by developing only the poles that cannot be arranged, which are calculated when calculating the control parameter, and the determination result is displayed on the display unit 111. If stable, the control parameter calculation unit 20 is notified to that effect, and the control parameter calculation unit 20 that has received the notification transfers the calculated control parameter to the control calculation unit 10 so that the servo control is executed. become.

  Next, a calculation method of the pole-zero arrangement formula in the automatic control device 1 to which the present invention is applied will be described. Incidentally, the calculation method of this pole-zero arrangement formula is almost the same as that disclosed in Japanese Patent Laid-Open No. 2000-322103.

  First, a pole-zero arrangement formula when there is a dead time component of one sampling time is obtained. FIG. 2 is a digital 2-degree-of-freedom PID control block diagram showing a control system constituted by the automatic control apparatus 1 to which the present invention is applied. In the block diagram of FIG. 2, the control parameter generation unit 18 is omitted. In such a case, first, a discrete transfer function P (z) obtained by z-transforming the drive motor M as a control target together with the 0th-order holder is expressed by equation (1).

  Here, the constants P, A, and B in the equation (1) are based on the equations (2) to (4), where the time constant of the first-order lag element is T0, the gain of the first-order lag element is K, and the sampling time is T. Calculated.

Further, the closed loop transfer function of the control system shown in FIG. 2 is expressed by equation (5).

In this equation (5), since the denominator is a quintic equation, there are five poles. Control parameters involved in the denominator equation is three _{K p, K d, K i} . Further, in the formula (5), the numerator is a cubic formula and there are three zeros. However, the zero point generated by (Bz + A) in the equation (5) is at a fixed position regardless of the control parameter. The zeros that can be arranged by the control parameters are two zeros generated by G _z (z), and the four control parameters that are involved are K _d , K _i , α, and β.

Here, with respect to the poles, five poles are arranged with three control parameters, so that two poles cannot be arranged. Regarding the zero point, four control parameters are involved. Of these, K _d and K _i are determined by the pole arrangement, so there are two control parameters α and β that can be used only for the zero point arrangement. Since there are two zeros to be arranged here, it can be seen that they can be arranged freely by α and β.

As described above, the automatic control device 1 to which the present invention is applied performs pole-zero arrangement as described below. That is, for the poles, the positions of the three poles are designated, and the control parameters K _p , K _d , and _Ki are acquired. For the zero point, the positions of the two zero points are specified, and the control parameters α and β are acquired. At this time, since information on two poles that cannot be arranged is also output, the stability determination unit 40 performs stability determination based on the information.

In the case of performing such stability determination, first, an equation for arranging the poles is calculated. When the three poles that can be placed are p ₁ , p ₂ , and p ₃ and the poles that cannot be placed are q ₁ and q ₂ , the closed-loop transfer function is expressed by equation (6).

Here, p ₁ , p ₂ , and p ₃ may be complex numbers. However, when one pole is a complex number, one of the remaining two poles needs to be a conjugate complex number.

  In addition, coefficient comparison expressions created so that the denominators of the expressions (5) and (6) are equal are expressed by the following expressions (7) to (11).

From this, when the equations are solved so that K _p , K _d , K _i , Q ₁ , Q ₂ are calculated, the pole placement equations (12) to (16) are obtained.

As a result, the control parameter calculation unit 20 outputs K _p , K _d , K _i , Q ₁ , Q ₂ with respect to the inputs p ₁ , p ₂ , p ₃ based on the equations (12) to (16). It is realized as a computing means. The stability determination unit 40 is realized as a device that stably determines whether all the roots of the equation (17) are within the unit circle.

As described above, the control parameters K _p , K _d , K ₂ can be obtained by calculating the coefficients Q ₁ , Q ₂ of the polynomial obtained by developing the poles q ₁ , q ₂ that cannot be arranged without calculating the unplaceable poles q ₁ , q _2. It can be confirmed that _i is calculated. Further, by using a general method as a stability determination method of the digital control system, such as the Jury method or the Schur-Cohn method, the poles q ₁ and q ₂ that cannot be arranged are calculated in the equation (17) which is the above polynomial. The stability determination can be performed without doing this.

Next, an expression for arranging the zeros is obtained. If two zeros that can be arranged are z ₁ and z ₂ , G _z (z) can be expressed by equation (18) based on equation (6).

Expressions (19) and (20) are obtained by expanding expression (18) and comparing the coefficients.

By obtaining α and β from equations (19) and (20), equations (21) and (22) are obtained.

As described above, by calculating the coefficients Q ₁ and Q ₂ of the polynomial (17) obtained by expanding the poles q ₁ and q ₂ that cannot be arranged in the control system having a calculation time delay of one sampling time, In addition, it is possible to derive an arrangement formula of zeros.

  Next, the case where the control system constituting the automatic control device 1 has a dead time element of two sampling times or more will be described.

  The automatic control device 1 to which the present invention is applied may have a large time delay element of one sampling time or more for some reason when controlling the operation of the angle to be controlled toward the target value. Even in such a case, as described below, a pole-zero arrangement formula is calculated for a closed-loop transfer function in which the dead time element is approximated to an integral multiple of the sampling time, and the control parameter calculation unit 20 and the stability determination unit 40 are configured using this. By doing so, more accurate pole arrangement can be realized.

First, the dead time element is approximated to an integral multiple of the sampling time, and calculation of the pole-zero arrangement formula when there is a dead time element of 2 sampling times will be described. A control system block diagram at this time is shown in FIG. In FIG. 3, it can be seen that the time delay element shown in FIG. ² is changed from 1 / z to 1 / z ² . The closed loop transfer function of this control system is expressed by equation (23).

In equation (23), the denominator is a sixth-order equation, so there are six poles. There are three control parameters as in the case of having a calculation time delay of one sampling time. Since six poles are arranged with these three control parameters, three poles that cannot be arranged are generated. When the three poles that can be placed are represented as p ₁ , p ₂ , and p _3, and the positions of the poles that cannot be disposed are represented as q ₁ , q ₂ , and q ₃ , the closed-loop transfer function is expressed by equation (24).

If a coefficient comparison expression is created so that the denominator expressions of Expressions (23) and (24) are equal, Expressions (25) to (30) are obtained.

From this _{K p, K d, K i} , as _{Q 1, Q 2, Q 3} is calculated (25) is solved to (30), (31) - (36) below the pole-zero placement formula Is obtained. Thus, the control parameter calculation unit 20 is realized by an arithmetic device that calculates K _p , K _d , K _i , Q ₁ , Q ₂ , and Q ₃ by inputting p ₁ , p ₂ , and p ₃ . The stability determining unit 40 is realized as a means for determining stably whether all the roots of the equation (37) are in the unit circle.

As described above, the control parameter K can be obtained by calculating the coefficients Q ₁ , Q ₂ , and Q ₃ of the polynomial obtained by developing the poles q ₁ , q ₂ , and q ₃ that cannot be arranged without calculating the poles q ₁ , q ₂ , and q _{3. p, K d,} can be calculated _{K i.} Further, by using a general method as a stability determination method of the digital control system, such as the Jury method or the Schur-Cohn method, with respect to the equation (37) which is the polynomial, the pole q ₁ , which cannot be arranged, is used. Stability determination can be performed without calculating q ₂ and q ₃ .

  As shown in the comparison between the equations (5) and (23), the zero can be obtained from the equations (21) to (22) as in the case where there is a dead time element of one sampling time.

  FIG. 4 is a flowchart showing the operation of the control parameter calculation unit 20 in the automatic control device 1 to which the present invention is applied.

First, in step S11, the control object gain K, the control target time constant T _0, sets the sampling time T. Then, the process proceeds to step S12, P and control object gain K set in step S11 described above, the control target time constant _{T 0,} by substituting the sampling time T (2) ~ (4) equation, A , B is calculated. The operation in step S12 may be executed only when the power is turned on.

Next, the process proceeds to step S13, and pole positions p ₁ , p ₂ , and p ₃ are input, and zero point positions z ₁ and z ₂ are input. Then the process proceeds to step S14, and calculates the _{Q 1} based on equation (31). Then the process proceeds to step S15, and calculates the _{Q 2} than in equation (32) using a _{Q 1} determined in step S14. Then the process proceeds to step S16, and calculates the _{Q 3} from equation (33).

Then the process proceeds to step S17, calculates the _{K p} based on equation (34). Then the process proceeds to step S18, calculates a _{K i} from equation (35). Next, the process proceeds to step S19, and _Kd is calculated from equation (36). Next, the process proceeds to step S20, and α is calculated by the equation (21). Next, the process proceeds to step S21, and β is calculated by equation (22).

Next, the process proceeds to step S22, and the values of Q ₁ , Q ₂ , Q ₃ are transferred to the stability determination unit 40 in order to determine the stability of the poles q ₁ , q ₂ , q ₃ that cannot be arranged, and the equation (37) Stability is discriminated whether all the roots exist in the unit circle. Specifically, it is conceivable to use a general method as a stability determination method for a digital control system, such as the Jury method or the Schur-Cohn method. If the stability determination result is unstable, the process proceeds to step S23, the display unit 111 displays that it is unstable, and the process ends. If the result of the stability determination is stable, the process proceeds to step S24 and notifies the control parameter calculation unit 20 to that effect, and the control parameter calculation unit 20 calculates K _p , K _d , K _i , α, β. Is output to the controller and the process ends. When the process proceeds to step S23, the user is prompted to decide whether or not to retry the above-described process, and the above-described process is repeated again when the user gives an intention to retry. Also good.

Here, the behavior of the poles q ₁ , q ₂ , q ₃ that cannot be arranged will be described. A pole that cannot be placed does not occur in a closed loop transfer function that does not assume a dead time element, but is due to a dead time element. When the servo band is low, the time constant of the control system is large, and the influence of the dead time element is relatively small. For this reason, the poles q ₁ , q ₂ , and q ₃ that cannot be arranged due to the dead time element also exist in a high-frequency region that does not greatly affect the control characteristics, specifically, near 0 in the z plane. As the servo band is widened, the influence of the dead time element becomes relatively large, and finally any of the poles q ₁ , q ₂ , q ₃ that cannot be arranged becomes unstable. This is considered the limit of the servo band of the digital servo control system. From the above, the poles q ₁ , q ₂ , q ₃ that cannot be arranged when the servo band is low exist in the vicinity of 0 and do not greatly affect the control characteristics. However, when increasing the servo bandwidth, it is necessary to pay attention to the poles q ₁ , q ₂ , and q ₃ that cannot be arranged. This is because if the servo band is too wide, any of the poles q ₁ , q ₂ , q ₃ that cannot be arranged becomes unstable, and this dominates the control performance limit.

It can be seen that in order to grasp the behavior of the poles q ₁ , q ₂ , q ₃ that cannot be arranged in this way, stability determination by the stability determination unit 40 is necessary.

  The operation of the control parameter calculation unit 20 in the digital two-degree-of-freedom PID control system having a dead time element of two sampling times has been described above.

  The present invention is not limited to the above-described embodiment, and the pole-zero arrangement formula can be similarly obtained by increasing the number of poles that cannot be arranged even after three sampling times or more. For poles that cannot be placed, the stability determination can be performed if the coefficient is known without specifically calculating the position of the pole, and thus whether or not the control parameter can be efficiently determined.

  In the present invention, redundant parameters for designating the pole and zero position may be omitted.

Normally, when specifying the pole positions p ₁ , p ₂ , and p ₃ , the parameters are specified by three parameters. In the case of all the real poles, p ₁ = a, p ₂ = b, and p ₃ = c. Specify three real numbers a, b, and c. Further, even when there are complex poles, they need to be conjugate, so that one set of conjugate complex poles and one real number pole are provided. Therefore, three real numbers a, b, and c are designated such as p ₁ = a + bj, p ₂ = a−bj, and p ₃ = c. Further, when the zeros z ₁ and z ₂ are designated, they are designated by two parameters. That is, in the case where all real numbers are zero, two real numbers f and g are designated such as z ₁ = f and z ₂ = g. In addition, since complex zeros need to be conjugate, two real numbers f and g are designated as z ₁ = f + gj and z ₂ = f−gj. As described above, in the pole-zero arrangement, five parameters are designated in combination with the pole and the zero point.

Usually, poles are often arranged in a stacked manner, but in general, real number poles have low vibration characteristics, and therefore, in the case of positioning control that avoids overshoot, three real number poles are often arranged. At this time, the influence of the pole with the slowest response becomes dominant, so that three real poles are stacked in order to make the response to the disturbance as fast as possible. Also, the zero point is often overlapped with the pole in order to speed up the response and clean the settling waveform. Therefore, it is often arranged such that p ₁ = p ₂ = p ₃ = z ₁ = z ₂ = a. Since it is cumbersome to input five of the same numerical values in normal input, only one real number a is designated. The operations of the control parameter calculation unit 20 and the stability determination unit 40 at this time are shown in FIG. In FIG. 5, the same operation steps as those in the flowchart shown in FIG. 4 described above are denoted by the same step numbers, and the description thereof is omitted by citing them.

As described above, in step S12, P, A, and B are calculated from the equations (2) to (4). Then, the process proceeds to step S31, and the pole position and the zero point position a are input. Next, the process proceeds to step S32, and pole positions p ₁ , p ₂ and p ₃ and zero positions z ₁ and z ₂ are generated from p ₁ = p ₂ = p ₃ = z ₁ = z ₂ = a, and step S14. Migrate to

  The above is a case where all the poles and zeros are real numbers, but other arrangements are possible. For example, in order to further accelerate the disturbance response, it is possible to arrange the poles in a Butterworth type and arrange the zeros so as to cancel the conjugate poles. In this case, two parameters are specified, but the purpose of omitting redundant parameters is the same.

  As described above, the automatic control apparatus 1 to which the present invention is applied can reduce the size of the dead time element included in the control system even in the digitized PID control system in which the dead time element is longer than one sampling time. The closed loop transfer function was calculated by approximating an integer multiple of the sampling time, and only the number of poles corresponding to the control parameter were placed. The other poles that could not be placed were calculated by calculating the coefficients of the polynomial obtained by expansion. The control parameter can be calculated based on the pole-zero arrangement formula. Further, whether or not the control system becomes unstable due to poles that cannot be arranged can be determined by applying a known stability determination method to the coefficients of the polynomial.

  As a result, even in a control system in which there is a dead time element of one sampling time or more, it is possible to realize pole placement more accurately and obtain desired control performance. In addition, since the stability determination can be performed, the control limit can be grasped more accurately and the control parameter can be adjusted more efficiently.

  In addition, it is not possible to separately designate all the poles that can be arranged at this time, but it is possible to easily obtain control parameters by omitting redundant numerical values by arranging the poles in an overlapping manner and reducing the designated numerical values.

  As described above, the automatic control device 1 according to the present invention can realize accurate control characteristics more easily.

  The present invention is not limited to the embodiment described above. For example, the present invention can be applied to an automatic control device 2 for controlling focus servo in an optical disc recording / reproducing device described below. Incidentally, the automatic control device 2 may control the tracking servo of a magnetic disk having a different actuator form and error signal detection method without departing from the scope of the invention. Incidentally, it goes without saying that the tracking servo in the optical disk may be controlled using the automatic control device 2.

  FIG. 6 shows the configuration of an optical disc recording / reproducing apparatus 3 in which an automatic control apparatus 2 to which the present invention is applied is provided.

  The optical disc recording / reproducing apparatus 3 outputs a control signal by executing predetermined arithmetic processing with a recording / reproducing element 31 for writing data to the optical disc 4 or reading data recorded on the optical disc 4. And a control parameter generation unit 28 that generates control parameters necessary for the control function in the control calculation unit 15.

  The recording / reproducing element 31 generates an error signal by focusing the light beam on each recording layer of the optical disk 4 to be rotated and detecting the return light reflected by the recording surface of the optical disk 4 to control this. It transmits to the calculating part 15. The recording / reproducing apparatus 31 is composed of a semiconductor laser or the like using semiconductor recombination emission, and receives a return light from the optical source 4 and a laser light source 32 that emits laser light of a predetermined wavelength and photoelectrically converts it. A light receiving unit 35 that guides the laser light emitted from the laser light source 32 to the optical disc 4 side, and transmits the laser light reflected by the optical disc 4 as it is to guide the laser light to the light receiving unit 35. And a lens 34 for condensing the laser light from the light separation unit 33 to focus on each recording layer of the optical disc 4 and making the return light from the optical disc 4 parallel light. And an electromagnetic actuator 36 for moving the recording / reproducing element 31 close to and away from the recording surface of the optical disc 4 in accordance with the control signal.

  The control calculation unit 15 in the automatic control device 2 detects an error signal generated in the light receiving unit 35, thereby generating an error signal detection circuit 51 that generates a focus error signal, and a focus error generated in the error signal detection circuit 51. By subjecting the AD converter 52 for A / D conversion of the signal and the focus error signal digitized by the AD converter 52 to predetermined control using the control parameter generated by the control parameter generator 28 A control arithmetic circuit 53 for generating a control signal, a DA converter 54 for D / A converting the control signal generated by the control arithmetic circuit 53, and an electromagnetic wave based on the control signal digitized by the DA converter 54 And an actuator driving circuit 55 for driving the actuator 36.

  Further, the control parameter generation unit 28 in the automatic control device 2 includes a control parameter calculation unit 41 that actually calculates the control parameters, a stability determination unit 42 connected to the control parameter calculation unit 41, and a connected stability determination unit 42. Are provided with a display unit 43 for displaying the result of stability determination and a pole position input unit 44 for setting a numerical value for the control parameter calculation unit 41.

  The control parameter calculation unit 41 calculates the control parameter used for each control function of the control calculation circuit 41 based on the numerical value specified by the pole position input unit 44, and outputs the calculation result to the control calculation circuit 53. To do.

  That is, the control parameter generation unit 28 generates control parameters necessary for the control calculation. Specifically, the pole position input unit 44 inputs a desired pole arrangement in the control system closed loop transfer function, and the control parameter calculation unit 41 calculates a control parameter for realizing the input pole arrangement. For poles that cannot be placed calculated when calculating the control parameter, the stability determination unit 42 performs stability determination, and the determination result is displayed on the display unit 43. If stable, the control parameter calculation unit 41 is notified to that effect, and the control parameter is transferred to the control arithmetic circuit 53, whereby the servo control of the recording / reproducing element 31 becomes possible.

  FIG. 7 shows a control block diagram when the control system constituting the automatic control device 2 having the above-described configuration is realized by digital control.

  In FIG. 7, r is a target position representing the position where the recording / reproducing element 31 should be. d is a disturbance such as runout of the disk applied to the target position. E represents a position error. This position error e corresponds to the difference r + dy between the target position r + d of the recording / reproducing element changed according to the disturbance d and the actual position y of the controlled object. In the control system shown in FIG. 7, the disturbance d applied to the recording / reproducing element 31 and the actual position y cannot be directly detected, and the error signal detection circuit 51 detects the position error e = r + d−y corresponding to the focus error signal. Servo control is performed.

The position error e is sampled and a control calculation is performed by the control calculation unit K (z). The control parameters of the control system are a low-frequency emphasized low-frequency cutoff discretization angular frequency a, a low-frequency emphasized high-frequency cutoff discretization angular frequency d, a phase advance discretization angular frequency b, a phase advance discretization angular frequency c, and among 5 is the controller gain K _p. After this control calculation, the calculation result is output after one sampling time. Incidentally, the calculation time delay in the control calculation unit K (z) corresponds to a dead time element in FIG. The output calculation result is output as a control signal u through the 0th order holder. The zero-order holder corresponds to the DA converter 54 in FIG. The actuator is driven by the control signal u to determine the position y of the recording / reproducing element. A transfer function from the control signal u to the position y of the recording / reproducing element is represented by a control object P (s) in FIG. Incidentally, in the present embodiment, the control object P (s) is represented by a quadratic integration element for simplicity.

  Further, the electromagnetic actuator 36 applied to the optical disc recording / reproducing apparatus 3 or the like is accurately represented by “first order integration + 1st order lag element” or “second order lag element having resonance characteristics”. However, in all cases, the difference is about 100 Hz or less, and the low frequency has a high gain and a large disturbance suppression effect, and therefore hardly affects the pole arrangement. For this reason, in the present embodiment, the electromagnetic actuator 36 is a Q-th order integration element for simplicity.

  Next, calculation of the pole placement equation will be described. The control object P (s) and the zeroth-order holder in FIG. 7 are z-transformed to P (z), and the whole is represented in FIG. 8 as a discrete system. The closed loop transfer function of this control system is expressed by equation (38).

In equation (38), the denominator is a quintic equation, so there are five poles. As described above, there are five control parameters. As described above, the low-frequency emphasis low-frequency cutoff discretization angular frequency a is governed by a factor other than the control performance, so the control parameters related to the control characteristics are There are actually four. Since five poles are arranged with four control parameters, one pole cannot be arranged. When the four poles that can be placed are represented as p ₁ , p ₂ , p ₃ , and p _4, and the position of the pole that cannot be placed is represented as q, the closed loop transfer function is expressed by equation (39).

  When the coefficient comparison formula is created so that the denominators of the formulas (38) and (39) are equal, the formulas (40) to (44) are obtained.

Solving the equation so that b, c, d, K _p , and q are calculated from this, the following pole arrangement equations (45) to (51) are obtained. Thus, the control parameter calculation unit 41 calculates b, c, d, K _p , and q with respect to the inputs p ₁ , p ₂ , p ₃ , and p ₄ according to equations (45) to (51). Realized in the device. The stability determination unit 42 is realized by a device that determines the authenticity of the equation (52).

  FIG. 9 is a flowchart showing the operations of the control parameter calculation unit 41 and the stability determination unit 42 described above.

First, in step S51, a low-frequency emphasis low-frequency cutoff discretization angular frequency a, a control target gain G _p , and a sampling time T are first set. The operation in step S51 may be performed only when the power is turned on.

Then, the process proceeds to step S52, and inputs the pole position _{p 1, p 2, p 3} , p 4. Next, the process proceeds to step S53, and q is calculated from equation (45). Next, the process proceeds to step S54, and b is calculated from equation (46) using q. Next, the process proceeds to step S55, and K _p is calculated from equation (47). Next, the process proceeds to step S56 to calculate cd from the equation (48), and further proceeds to step S57 to calculate c + d from the equation (49).

  Next, the process proceeds to step S58, and c and d are obtained based on equations (50) and (51). When c and d are complex complex numbers, it is necessary to realize not a series of primary filters but a secondary filter at the time of mounting. Next, the process proceeds to step S59, where the value of the pole q that cannot be arranged is transferred to the stability determination unit 40, and the stability determination unit 40 performs stability determination based on the equation (52). If equation (52) does not hold, it is unstable and the process proceeds to step S60. On the other hand, when the formula (52) is established, the process proceeds to step S61.

If the routine moves to step S61, and notifies the control system is stable to the control parameter calculator 41, the control parameter calculator 41 which receives the, b calculated himself, c, d, and K _p control It outputs to the calculating part 15, and complete | finishes a process.

On the other hand, when the process proceeds to step S60, it is displayed on the display unit 43 that the control system is unstable, and then the process proceeds to step S62 to ask the user whether to retry the above-described processing. Prompt selection. As a result, when the user selects to retry the above-described processing, the process proceeds to step S62 again, and the pole positions p ₁ , p ₂ , p ₃ , and p ₄ are input. If the user selects not to retry the above-described process, the process ends.

  Here, the behavior of the pole q that cannot be arranged will be described. A pole that cannot be placed does not occur in a closed-loop transfer function that does not assume a dead time element, but is caused by a dead time element. When the servo band is low, the time constant of the control system is large, and the influence of the dead time element is relatively small. For this reason, the pole q that cannot be arranged due to the dead time element also exists in a high-frequency region that does not greatly affect the control characteristics, specifically in the vicinity of 0 in the z plane. As the servo band is expanded, the influence of the dead time element also becomes relatively large, and finally the pole q that cannot be arranged becomes unstable. This is considered the limit of the servo band of the digital servo control system. From the above, when the servo band is low, the pole q that cannot be arranged exists in the vicinity of 0 and does not greatly affect the control characteristics. However, it is understood that when the servo band is widened, it is necessary to pay attention to the pole q that cannot be arranged.

Next, regarding the control characteristics when the control parameters are generated in the pole arrangement, in the control system shown in FIG. 8, the control target G _p = 400000000, the sampling time 2 μs, and the low frequency emphasis low frequency cutoff discretization angular frequency a = 0.999937 (corresponding to 5 Hz) is described as an example.

In the conventional control parameter determination method, the phase lag frequency is approximately three times the zero cross frequency of the open loop gain frequency characteristic and the phase advance frequency is also approximately one third, and the high frequency cutoff frequency for low frequency emphasis is the above zero cross frequency. The frequency is set so as not to affect the phase margin in the vicinity. FIGS. 10A and 10B show the open loop frequency characteristics of the control system of FIG. 8 when the control parameters are obtained by the control parameter determination method for the above-described control target. According to the control parameter determination method, the zero cross frequency is set to 6 kHz, the phase advance frequency is set to 2 kHz, the phase delay frequency is set to 18 kHz, the high frequency cutoff frequency of the low frequency emphasis is set to 100 Hz. The phase delay discretization angular frequency b = 0.79756, the low frequency emphasis high frequency cutoff discretization angular frequency c = 0.998984, and the phase advance discretization angular frequency d = 0.975182. Further, by adjusting the gain _{K p} to zero crossing at 6 _kHz, and the K p = 9.706.

The poles of the closed-loop transfer function at this time are 0.987444, 0.953173, 0.927394 ± 0.053766j. In addition, the position of the pole corresponding to the pole q that cannot be arranged is −0.009206. Nearly zero and does not affect stability. Further, FIG. 11 shows a disturbance response simulation result of the position error e when a step torque disturbance is input to _dt in FIG. Although the position error e increases due to the torque disturbance _dt , it gradually decreases due to the disturbance suppression characteristic of the control system, and finally converges to a constant value of 0.09.

Here, based on the pole arrangement, when considering how to improve the disturbance response characteristics, generally in a discrete system, the closer the pole is to 0, the faster the response. When there are a plurality of poles, the influence of the pole closest to 1 (that is, the slow response) is dominant. Referring to the above property, first, the convergence with respect to the disturbance input is accelerated. Place the slowest response pole 0.987444 (equivalent to 100Hz) at 0.996237 (equivalent to 300Hz) and leave the other poles intact. When the control parameters are obtained from the flowchart shown in FIG. 9, the phase delay discretization angular frequency b = 0.947745, the low frequency emphasis high frequency cutoff discretization angular frequency c = 0.996204, the phase advance discretization angular frequency d = 0.976149 and the gain K _p = 10.024. The position of the pole q that cannot be arranged is close to the above example and is −0.009516, and it can be seen that the stability is not affected.

  Next, the disturbance response simulation result is shown as pole arrangement A in FIG. FIG. 12 shows that the disturbance converges faster than the disturbance response with the conventional control parameters. Further, the open loop frequency characteristic is shown as a pole arrangement A in FIGS. 13 (a) and 13 (b). In FIG. 13, it is confirmed that the low-frequency gain is increased.

Next, the peak of the disturbance response is reduced. The rising part of the disturbance response is considered to have many high frequency components close to the impulse. Therefore, the pole with the fastest response 0.927394 ± 0.053766j (equivalent to 7.5 kHz) is arranged at a faster position 0.857169 ± 0.099723j (equivalent to 15 kHz), and the other poles are left in the initial arrangement. When the control parameters are obtained according to the flowchart of FIG. 9, the phase lag discretization angular frequency b = 0.6479, the high frequency cutoff high frequency cutoff discretization angular frequency c = 0.998744, and the phase advance discretization angular frequency d = 0. .968301 and the gain K _p = 28.889. The position of the pole q that cannot be arranged is -0.031528, which is slightly large, but is almost zero and does not affect the stability.

  Moreover, the disturbance response simulation result in such a case is shown as a pole arrangement B in FIG. It can be seen from FIG. 14 that the peak of the disturbance response is small. The open loop frequency characteristic is shown as pole arrangement B in FIGS. 15 (a) and 15 (b). According to FIG. 15, the gain is increased as a whole, and the zero cross frequency is also increased.

  As described above, by specifying the pole position of the closed-loop transfer function that is directly connected to the closed-loop characteristic, the control characteristic can be directly specified.

  The above example is an example of pole arrangement in a control system having a calculation time delay of one sampling time in FIG. 8, but in reality, there may be a dead time element of one sampling time or more for some reason. Even in such a case, the pole placement equation is calculated for the closed-loop transfer function in which the dead time element is approximated to an integral multiple of the sampling time as follows, and the control parameter calculation unit 41 and the stability determination unit 42 are configured using this. A more accurate pole arrangement can be realized.

For example, the calculation of the pole placement formula when the dead time element is approximated to an integral multiple of the sampling time and there is a dead time element of 3 sampling times will be described. A control system block diagram at this time is shown in FIG. Compared to FIG. 8, the dead time element is changed from 1 / z to 1 / z ³ . The closed loop transfer function of this control system is expressed by equation (53).

In the equation (53), since the denominator is a seventh-order equation, there are seven poles. The control parameters are substantially four as in the case where there is a calculation time delay of one sampling time. Since seven poles are arranged with four control parameters, three poles cannot be arranged. When the four poles that can be placed are represented as p ₁ , p ₂ , p ₃ , and p _4, and the positions of the poles that cannot be placed are represented as q ₁ , q ₂ , and q ₃ , the closed-loop transfer function is expressed as equation (54).

When the coefficient comparison formula is created so that the denominator formulas of the formulas (53) and (54) are equal, the following formulas (55) to (61) are obtained.

Solving the equations so that b, c, d, K _p , Q ₁ , Q ₂ , Q ₃ are calculated from these, the pole placement equations (62) to (70) are obtained. Thus, the control parameter calculation unit 28 is realized by an arithmetic unit that calculates b, c, d, K _p , Q ₁ , Q ₂ , and Q ₃ by inputting p ₁ , p ₂ , p ₃ , and p _4. Is done. The stability determination unit 42 is realized as a means for determining stability whether all roots of the following equation (71) are within the unit circle.

  FIG. 17 is a flowchart showing the operations of the control parameter calculation unit 41 and the stability determination unit 42.

First, in step S71, first, a low-frequency emphasis low-frequency cutoff discretization angular frequency a, a control target gain G _p , and a sampling time T are set. Next, the process proceeds to step S72, and the pole positions p ₁ , p ₂ , p ₃ and p ₄ are input. Then the process proceeds to step S73, and calculates the _{Q 1} from equation (62). Then the process proceeds to step S74, _{Q 1} also calculates the _{Q 2} than in (63) below using. Then the process proceeds to step S75, the calculating the _{Q 3} from (64) below. Next, the process proceeds to step S76, and b is calculated from equation (65). Next, the process proceeds to step S77, and K _p is calculated from equation (66). Next, the process proceeds to step S78, where cd is calculated from equation (67), and c + d is calculated from equation (68) in step S79.

In step S80, c and d are obtained from equations (69) and (70). When c and d are complex complex numbers, it is necessary to realize not a series of primary filters but a secondary filter at the time of mounting. Next, the process proceeds to step S81, and the values of Q ₁ , Q ₂ , and Q ₃ are transferred to the stability determination unit 42 in order to determine the stability of the poles q ₁ , q ₂ , q ₃ that cannot be arranged, and all of the equations (71) are transferred. Stability is determined whether or not the root of is in the unit circle. Specifically, a general technique such as Jury's method or Schur-Cohn's method may be used as a stability determination method for a digital control system.

  If the result of the stability determination in step S81 is unstable, the process proceeds to step S83, indicating that the display unit 43 is unstable, and further proceeds to step S84 to retry the above-described processing. The user is prompted to select whether or not. As a result, when the user instructs to retry the above-described processing, the process proceeds to step S72 again and the pole position is input. On the other hand, if the user instructs not to retry, the process ends.

On the other hand, if the result of the stability determination in step S81 is stable, the control parameter calculation unit 41 is notified to that effect, and the control parameter calculation unit 41 uses the calculated b, c, d, and K _p as a control calculation. It outputs to the part 15 and complete | finishes.

  As described above, even in a control system having a large dead time such as the automatic control device 2, the pole placement equation can be calculated by approximating the size of the dead time element to an integral multiple of the sampling time. As a result, the number of poles that cannot be controlled increases as compared with a case where a dead time of one sampling time is assumed, but the poles can be specified accurately for the number of control parameters. Thereby, even in a control system having a dead time longer than one sampling time, it is possible to directly specify a control characteristic at the pole position of the closed-loop transfer function and obtain a control parameter by the pole placement method. At this time, the pole placement can be realized accurately by calculating the control parameter according to the pole placement formula (calculation formula) derived from the closed loop transfer function including the dead time approximated to an integral multiple of the sampling time. The desired control performance can be obtained. In addition, the control parameter generation unit 28 includes a stability determination unit 42 that determines whether there are no poles that cannot be specified in the above-described pole arrangement formula outside the unit circle, and displays these if there are poles outside the unit circle. Unstable operation can be prevented, and a simpler and more accurate control characteristic can be realized.

It is a block diagram of the automatic control apparatus to which this invention is applied. FIG. 3 is a digital two-degree-of-freedom PID control block diagram showing a control system constituted by an automatic control device to which the present invention is applied. It is a control system block diagram in the case where there is a dead time element of two sampling times in a control system constituted by an automatic control device to which the present invention is applied. It is a flowchart which shows operation | movement of the control parameter calculation part in the automatic control apparatus to which this invention is applied. It is a flowchart which shows operation | movement of the control parameter calculation part and stability determination part in the case of designating only one real number a. 1 is a configuration diagram of an optical disc recording / reproducing apparatus provided with an automatic control apparatus to which the present invention is applied. It is a control block diagram when the control system which comprises an automatic control apparatus is implement | achieved by digital control. FIG. 10 is a control block diagram in which a zero-order holder is z-transformed to P (z), and the entire control system is represented by a discrete system. It is another flowchart which shows operation | movement of a control parameter calculation part and a stability discrimination | determination part. It is a figure which shows the open loop frequency characteristic of a control system when a control parameter is calculated | required with the conventional control parameter determination method. It is a figure which shows the disturbance response simulation result when step torque disturbance is further input under the conventional control parameter determination method. It is a figure which shows the disturbance response simulation result calculated | required under the control parameter determination method by the automatic control apparatus to which this invention is applied. It is a figure which shows the open loop frequency characteristic of a control system at the time of calculating | requiring a control parameter with the automatic control apparatus to which this invention is applied. It is a figure which shows the other disturbance response simulation result calculated | required under the control parameter determination method by the automatic control apparatus to which this invention is applied. It is a figure which shows the other open loop frequency characteristic of a control system at the time of calculating | requiring a control parameter with the automatic control apparatus to which this invention is applied. It is a control system block diagram when there is a dead time element of 3 sampling times. It is a flowchart which shows operation | movement of the control parameter calculation part and stability determination part when there exists a dead time element of 3 sampling time. It is a block diagram of the conventional control apparatus. It is a figure for analyzing stability in z coordinate system about a controlled object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic control apparatus, 10 Control calculating part, 18 Control parameter production | generation part, 20 Control parameter calculation part, 30 pole zero arrangement | positioning input part, 40 Stability determination part, 50 D / A conversion circuit, 60 Motor driver, 70 Encoder, 80 Sampler Circuit, 111 display

Claims (18)

In an automatic control device configured by a closed loop that controls the operation of an angle or a position of a control target toward a target value based on the generated control signal,
Differential signal generating means for generating a differential signal according to a difference of the current angle or position of the control target with respect to the target value;
The control parameter for controlling the operation of the controlled object is calculated, and a predetermined calculation process is performed on the difference signal generated by the difference signal generation unit based on a control function using the calculated control parameter. Control arithmetic means for generating a control signal,
The automatic control apparatus, wherein the control calculation means calculates the control parameter from the pole of the closed loop transfer function in the closed loop based on an arithmetic expression including a time delay element in the automatic control apparatus. The control calculation means calculates the closed-loop transfer function by approximating a dead time element in the automatic control device to an integer multiple of the sampling time, and arranges the poles of the closed-loop transfer function according to the number of control parameters. The automatic control device according to claim 1, wherein the control parameter is calculated based on a pole placement formula obtained by calculating a coefficient of a polynomial for other poles that cannot be placed. The automatic control apparatus according to claim 2, wherein the control calculation unit performs stability determination on the pole that cannot be arranged, and notifies the user of the result of the stability determination. A recording / reproducing element as the control target for writing data to the disk-shaped recording medium or reading data recorded on the disk-shaped recording medium;
Driving means for driving the recording / reproducing element in a horizontal direction or a vertical direction with respect to a recording surface of the disc-shaped recording medium;
An error signal detecting means for detecting an error signal that is proportional to the difference between the position where the recording / reproducing element should perform recording and reproduction and the actual position and that detects an error signal corresponding to the difference signal;
The automatic control apparatus according to claim 1, wherein the control calculation unit calculates a control parameter for controlling the operation of the driving unit. The control calculation means calculates the control parameter based on an arithmetic expression including a dead time element in the automatic control device configured by a closed loop that performs PID control of the angle or position of the control target toward a target value. The automatic control apparatus according to claim 1. The control calculation means calculates the closed-loop transfer function by approximating a dead time element in the automatic control device to an integer multiple of the sampling time, and arranges the poles of the closed-loop transfer function according to the number of control parameters. The automatic control device according to claim 5, wherein the control parameter is calculated based on a pole placement formula obtained by calculating a coefficient of a polynomial for other poles that cannot be placed. The automatic control apparatus according to claim 6, wherein the control calculation unit performs stability determination on the pole that cannot be arranged, and notifies the user of the result of the stability determination. Electromagnetic driving means for rotating the magnetized rotor according to the control signal generated by the control calculation means;
The difference signal generation means generates a difference signal corresponding to the difference with respect to the target value of the current rotation angle of the rotor as the control target,
The automatic control apparatus according to claim 5, wherein the control calculation means calculates a control parameter for controlling the operation of the electromagnetic drive means. In an automatic control method for controlling the operation of an object to be controlled in an angle or position toward a target value in a closed loop based on the generated control signal,
A difference signal generation step for generating a difference signal according to a difference with respect to the target value of the current angle or position of the control target;
A control parameter for controlling the operation of the control target is calculated, and the control is performed by performing a predetermined calculation process on the difference signal generated in the difference signal generation step based on a control function using the calculated control parameter. A control operation step for generating a signal,
In the control calculation step, the control parameter is calculated from the pole of the closed loop transfer function in the closed loop based on an arithmetic expression including a dead time element in the closed loop. In the control calculation step, the dead time element in the closed loop is approximated to an integral multiple of the sampling time to calculate the closed loop transfer function, and the poles of the closed loop transfer function according to the number of control parameters are arranged, The automatic control method according to claim 9, wherein for the other poles that cannot be arranged, the control parameter is calculated based on a pole arrangement formula obtained by calculating a coefficient of a polynomial. The automatic control method according to claim 10, wherein in the control calculation step, stability determination is performed for the pole that cannot be arranged, and a result of the stability determination is notified to the user. In the differential signal generating step, the target value of the current position of the recording / reproducing element as the control target for writing data to the disk-shaped recording medium or reading data recorded on the disk-shaped recording medium Generate a difference signal according to the difference with respect to
In the control calculation step, a control parameter for controlling operation of a drive unit for driving the recording / reproducing element in a horizontal direction or a vertical direction with respect to a recording surface of the disc-shaped recording medium is calculated. The automatic control method according to claim 9. The control parameter is calculated in the control calculation step based on an arithmetic expression including a dead time element in a closed loop in which the angle or position of the control target is PID controlled toward a target value. Automatic control method. In the control calculation step, the dead time element in the closed loop is approximated to an integral multiple of the sampling time to calculate the closed loop transfer function, and the poles of the closed loop transfer function according to the number of control parameters are arranged, 14. The automatic control method according to claim 13, wherein for the other poles that cannot be arranged, the control parameter is calculated based on a pole arrangement formula obtained by calculating a coefficient of a polynomial. The automatic control method according to claim 14, wherein in the control calculation step, stability determination is performed for the pole that cannot be arranged, and a result of the stability determination is notified to the user. In the difference signal generation step, a difference signal corresponding to the difference with respect to the target value of the current rotation angle of the magnetized rotor as the control target is generated,
The automatic control method according to claim 13, wherein the control calculation step calculates a control parameter for controlling the operation of an electromagnetic drive unit that rotates the rotor. Based on the generated control signal, it is configured by a closed loop that controls the operation of the angle or position of the control target toward the target value, and generates a difference signal corresponding to the difference of the current angle or position of the control target with respect to the target value. For a control apparatus having a difference signal generation means and a control means for generating the control signal by performing a predetermined arithmetic processing based on a control function for the difference signal generated by the difference signal generation means In a control parameter generation device for supplying control parameters constituting a control function,
Comprising a parameter calculating means for calculating a control parameter for controlling the operation of the controlled object,
The control parameter generation device characterized in that the parameter calculation means calculates the control parameter from a pole of a closed loop transfer function in the closed loop based on an arithmetic expression including a time delay element in the automatic control device. Based on the generated control signal, it is configured by a closed loop that controls the operation of the angle or position of the control target toward the target value, and generates a difference signal corresponding to the difference of the current angle or position of the control target with respect to the target value. For a control device having a difference signal generation unit and a control unit that generates the control signal by performing predetermined arithmetic processing based on a control function for the difference signal generated by the difference signal generation unit. In a control parameter generation method for supplying control parameters constituting a control function,
A parameter calculating step for calculating a control parameter for controlling the operation of the controlled object;
In the parameter calculation step, the control parameter is calculated from the pole of the closed loop transfer function in the closed loop based on an arithmetic expression including a time delay element in the control device.

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